Package party.iroiro.luajava

Interface JFunction

public interface JFunction
Functional alternative to C closures in Lua to allow, for example, lambda grammar

  • Method Summary

    Modifier and Type
    Method
    Description
    int
    __call(Lua L)
    The function body

  • Method Details

    • __call

      int __call(Lua L)
      The function body

      The call follows the protocol of lua_CFunction with a bit of modification:

      In order to communicate properly with Lua, a C function must use the following protocol, which defines the way parameters and results are passed: a C function receives its arguments from Lua in its stack in direct order (the first argument is pushed first). So, when the function starts, lua_gettop(L) returns the number of arguments received by the function. The first argument (if any) is at index 1 and its last argument is at index lua_gettop(L). To return values to Lua, a C function just pushes them onto the stack, in direct order (the first result is pushed first), and returns the number of results. Any other value in the stack below the results will be properly discarded by Lua. Like a Lua function, a C function called by Lua can also return many results.

      To yield a Lua error, push an error message onto the top of the stack and return -1.

      Parameters:
      L - the current lua state
      Returns:
      the number of return values pushed onto the stack (-1 to indicate an error)